To prevent occurrence of abnormal noise according to displacement in axial direction of the hub 4a and a driving shaft member 18b, and to secure durability by a structure facilitating assembly work.

The hub 4a is connected with the driving shaft member 18b by means of a snap ring 33. A shock absorbing ring 45 is sandwiched and held between the hub 4a and the driving shaft member 18b to prevent the occurrence of the abnormal noise. Elastic force of boots 53a disposed on a side of a constant velocity universal joint 49 on a differential side is larger than the elastic force of boots 53b disposed on a constant velocity universal joint 2b on a vehicle wheel. By the constitution, even if the shock absorbing ring 45 is in fatigue, the function of the shock absorbing ring is secured to solve the problem.